Chapter 7.1

Momentum


Momentum is inertia in motion.

momentum=mass x velocity


Chapter 7.2

Impulse Changes Momentum


Force produces accelertaion. When the force is increased the change in momentum and velocity also increases.

Impulse = force x time

Impulse = change in momentum


The greater the impulse, the greater the change in momentum.
In order to increase momentum, apply the greatest force possible for as long as possible.
In order to decrease momentum, decrease the impact time.
A longer impact time reduces force.
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Chapter 7.3

Bouncing

Bouncing increases impulse.

Chapter 7.4

Conservation of Momentum

To change momentum exert an impulse.
Without a net force there cannot be a change in momentum
Momentum is a vector quantity, having magnitude and direction.
If no net force acts on the system then no change in momentum can take place within that system.
Conservation of Energy:

In the absense of external force, the momentum of the system remains unchanged.

When momentum does not change it is conserved.
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Chapter 7.5

Collisions


Elastic Collsions is when two objects collide, but do not produce heat and are not permanantly altered.

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An inelastic collisions is when two objects collide and stay together.
Both forms of collisions show the conservation of momentum:

net momentum (before collision)=net momentum (after collision)

Collsions ususally involve external forces, which usually have little consequence during the collision so the net momentum does not change during impact.


Chapter 7.6

Momentum Vectors

Momentum is conserved when objects do not move in a straight path.
Momentum is a vector quantity.
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The total momentum of the crash of the car is the momentum of car A and car B before the collision. If the momentum of car A and car B are equil the combined momentum after the collision will be in a northeast direction and is .212 times the momenton of either car A or B before the collision.